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A128469
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Numbers of the form 30k+29 or possible lower bounds of twin primes pairs ending in 9.
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1
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29, 59, 89, 119, 149, 179, 209, 239, 269, 299, 329, 359, 389, 419, 449, 479, 509, 539, 569, 599, 629, 659, 689, 719, 749, 779, 809, 839, 869, 899, 929, 959, 989, 1019, 1049, 1079, 1109, 1139, 1169, 1199, 1229, 1259, 1289, 1319, 1349, 1379, 1409, 1439, 1469
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OFFSET
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1,1
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COMMENTS
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For a 30k+r "wheel", r = 11,17,29 are the only possible values that can form a a lower twin prime pair. The 30k+r wheel gives the recurrence 1, 7,11,13,17,19,23,29 31,37,41,43,47,49,53,59 .. which is frequently used in prime number sieves to skip multiples of 2,3,5. The fact that adding 2 to 30k+1,7,13,19,23 will gives us a multiple of 3 or 5, precludes these numbers from being a lower member of a twin prime pair. This leaves us with r = 11,17,29 as the only possible cases to form a lower bound of a twin prime pair. The lower bound of twin prime pairs can only end in 1,7 or 9 since adding 2 to primes ending in 3 become multiples of 5.
Of the first 10000 terms of this sequence, only 988 are lower primes of a twin prime pair. [From Harvey P. Dale, May 05 2011]
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LINKS
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Table of n, a(n) for n=1..49.
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EXAMPLE
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59 = 30*1 + 29, the lower part of the twin prime pair 59,61.
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MATHEMATICA
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30Range[0, 60]+29 (* Harvey P. Dale, May 05 2011 *)
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PROG
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(PARI) g(n) = forstep(x=29, n, 30, print1(x", "))
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CROSSREFS
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Sequence in context: A042668 A042664 A042662 * A132236 A293425 A158477
Adjacent sequences: A128466 A128467 A128468 * A128470 A128471 A128472
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KEYWORD
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easy,nonn
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AUTHOR
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Cino Hilliard, May 05 2007
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STATUS
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approved
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